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UNITED STATES DEPARTMENT OF AGRICULTURE 



BULLETIN No. 569 

Contribution from the Bureau of Chemistry 
CARL L. ALSBERG, Chief 



Washington. D. C. 


V 


June 25, 1917 


THE SANITARY CONTROL OF TOMATO-CANNING 

FACTORIES. 


By Burton J. Howard, Microscopist in Charge , in collaboration with Charles 


• / 


H. Stephenson, Scientific Assistant, Microchemical Laboratory. 


CONTENTS. 


Page. 


Introduction. 1 

Conditions observed in several tomato¬ 
canning factories. 3 

Washing. 8 

Sorting: 

Its importance. 10 

Sorting systems. 11 

Uniformity and rate of feeding. 14 

Turning devices. 15 

Lighting the sorting tables. 16 

Sorters. 17 

Volume sorted. 17 

Efficiency of sorting. 18 


Page. 


Sorting—Continued. 

Cost of sorting. 20 

Trimming. 20 

Pulping. 21 

Pulp-making systems. 21 

Promptness in handling stock. 23 

Cleanliness in the factory: 

Its importance. 24 

The necessary equipment. 25 

Use of equipment. 25 

Psychology of cleanliness. 26 

Laboratory control. 27 

Summary. 28 


INTRODUCTION. 


Marked changes in machinery and methods for the manufacture of 
food products have been made in the last 6 or 8 years under the 
stimulus of Federal and State pure food and sanitary laws. The 
manufacturer has come to appreciate the need for more sanitary 
methods. Certain individuals, firms, and corporations, of their own 
initiative, have blazed a path out of questionable or unsanitary sur¬ 
roundings in advance of Federal or State laws imposing such re¬ 
forms. Much credit is due manufacturers of this type who are willing 
to improve their methods of manufacture regardless of the existence 
or nonexistence of laws making such improvements imperative. At 
the other extreme is that small class of manufacturers who are in¬ 
different to the character of their product, either from the standpoint 

100635°—Bull. 569—17-1 






























































2 


BULLETIN 569, U. S. DEPARTMENT OF AGRICULTURE. 


of sanitation or from that of quality, as long as their product can be 
disposed of at a financial profit. 

Between these two extreme types of manufacturers, one of which 
is alert and active in seeking constantly to improve conditions, and 
the other of which is devoid of care or interest in the business beyond 
the financial profit obtainable, there is a third and much larger class. 
This class comprises those men who are willing to make improve¬ 
ments in keeping with sound, sanitary practice, but whose experience, 
because of the purely commercial aspects of their business, has given 
them no opportunity personally to study the sanitary problems of 
their factories and to apply the information gained in a practical 
manner. In other words, many manufacturers are deterred from 
making improvements because of lack of knowledge either of the 
fundamental reasons for such improvements or of how to proceed. 

The willingness of this class of manufacturers to make improve¬ 
ments, however, has rendered possible the great changes that have 
taken place in recent years in mechanical contrivances for cleaning 
a*nd handling the various products used in the manufacture of foods. 
This progress is especially well illustrated in the tomato industry. 
For example, only a few years ago the sorting of tomatoes in the 
manufacture of ketchup and pulp w T as very uncommon, while to-day 
very few manufacturers do not at least profess to observe this step, 
however ineffectively the process sometimes may be performed. Vari¬ 
ous forms of tables and machines have been devised to assist in this 
important step of manufacture. Many forms of tomato-washing 
machines found in common use 6 or 7 years ago have become so 
obsolete that they are being consigned rapidly to the scrap heap as 
inadequate to meet present-day requirements. Processes, such as the 
“ gravity system” of draining off the watery juice from pulp which 
w T as so very largely practiced less than 10 years ago, have been dis¬ 
carded by firms that are trying to keep abreast of their fellow manu¬ 
facturers in matters of sanitation and quality. The custom of storing 
in barrels—general a few years ago—has now T practically disappeared, 
except for the poorest grades of products. The barrel has been re¬ 
placed by the 5 or 6 gallon tin can. The writer recalls having seen 
at one plant thousands of barrels in one lot being offered for sale 
because the firm had no further use for them, as it had adopted the 
more satisfactory system of storing its product in cans. 

The manufacture of sanitary food products is too broad a problem 
to be covered in one publication. In the present bulletin the discus¬ 
sion will be limited to those conditions which apply particularly to 
tomato-canning factories. It is proposed to discuss some of the more 
important points concerning sanitary control of plants of this kind 
in a rather elementary manner and to avoid technicalities as far as 
possible. # ; 

D. Of D. 

JUL 7 1917 


SANITARY CONTROL OF TOMATO-CANNING FACTORIES. 


3 


CONDITIONS OBSERVED IN SEVERAL TOMATO-CANNING 

FACTORIES. 

Criteria of cleanliness are involved in the question of what con¬ 
stitutes a sanitary plant or product. Under the Food and Drugs Act, 
June 30, 1906, the Federal Government has no power to enforce sani¬ 
tary rules except as it may prohibit the entrance into interstate com¬ 
merce of products which are filthy, decomposed, or putrid. 1 Direct 
control over the factories themselves is wholly within the jurisdiction 
of the several States; the Federal Government can serve only in an 
advisory capacity. Various States have sanitary regulations, but in 
formulating them general terms must be used. Hence, in applying 
these regulations to specific cases considerable difference of opinion 
may appear because of the variation in training or experience of 
those making the inspection. It is easier to direct that “ products 
shall be made in a sanitary manner ” than to explain in concrete 
terms what is meant by these words. Therefore, it seems appropriate 
to tell of the conditions found in a few factories and what was done 
to correct them. These examples are cited not because they represent 
the average condition of tomato-canning factories throughout the 
country but because they illustrate conditions in a rather large class 
of establishments where the superintendents are sincere in consider¬ 
ing their plants satisfactory when, as a matter of fact, their factories 
may be seriously deficient in some particulars. 

At hearings held in connection with the enforcement of the Federal 
Food and Drugs Act it has occurred repeatedly that the manufac¬ 
turers concerned have claimed that their products were made under 
absolutely sanitary conditions. Obviously, it is rarely possible to 
verify such statements by inspection, principally because the season 
when the goods were packed has already passed and the factory is 
more or less dismantled. Usually it is of little value to visit a plant 
in the out-of-season periods of the year if a study of sanitation under 
working conditions is desired. Such claims on the part of the manu¬ 
facturers usually may be considered as candid and honest expressions 
of opinion, but field work has shown that lack of experience in mat¬ 
ters of sanitation may produce very erroneous conclusions. 

Factory No. 1. 

About the middle of a recent tomato-packing season the following 
letter from a manufacturer of tomato products was received by the 
Bureau of Chemistry: 

We wish to call your personal attention to a condition that is existing in the 
tomato-ketchup business as regards our own plant and, as we believe, the 
same condition exists in many other plants. 

1 For the views of various Federal courts upon what constitutes a filthy, decomposed, 
or putrid product see Notices of Judgment 544, 649, 825, 873, 1693, 3372, 3400, and 
4036 ; also National Canners Asso. Bui, 38, Jap. 20. 1917, Washington, D. C. 



4 


BULLETIN 569, U. S. DEPARTMENT OF AGRICULTURE. 


We are getting from the farmer a high-grade tomato, one that is perfectly 
sound and ripe. We are trimming our tomatoes very carefully and washing 
them in three different waters. 

Reports from our chemist * * * showed our earlier run to be: 


Mold. 

Yeast and spores. 

Bacteria. 

In 7 per cent of fields... 
In 9 per cent of fields... 

6 in 1/60 cmm. 

10,500,000 per cc. 
9,500,000 per cc. 

7 in 1/60 cmm. 



Since then it has been gradually increasing until our last report shows the 
following: 


52 per cent of fields. 

28 in 1/60 cmm. 

21,000,000 per cc. 

44 per cent of fields. 

28 in 1/60 cmm. 

24,000,000 per cc. 


It is absolutely impossible for any human being and under any conditions to 
take tomatoes and manufacture a ketchup any more cleanly, any freer from 
mold or bacteria than the ketchup we are producing. There isn’t a ketchup 
factory in the United States more cleanly or sanitary than ours. We are 
satisfied that this mold, yeast and spores, and bacteria is in the tomato in its 
healthy condition, that is, in perfectly sound tomatoes. 

We know no one would condemn these tomatoes as being unfit for food. 
We are endeavoring to comply with the food law standard that has been estab¬ 
lished on tomato ketchup, but we can not go out of business simply because 
these standards have been made without due knowledge of the real chemical 
analysis of a perfectly sound, fresh tomato under all conditions, and when the 
raw product brought from the farmers is delivered to our plant and handled 
in a perfectly sound, clean, wholesome condition, we can not understand why 
our goods, which are strictly high-grade and pure, should be condemned by the 
Department of Agriculture under conditions of this kind. 

We will very much appreciate if you will wire us just what to do. Also 
that you would have one of your representatives at our plant as quickly as 
he can get here, as we feel that we are entitled to the services of one of your 
personal representatives, as we know that our goods are right. 

We know that they can not be manufactured under any more cleanly con¬ 
ditions than we are carrying out. We are therefore willing and entitled to 
make a stand on this, believing that the Agriculture Department will recog¬ 
nize the condition and protect us against any results that might come from 
our goods being picked up by food inspectors among our customers after they 
have left our warehouse. 

Thanking you, and trusting that you will give this your immediate attention, 
we are, 

Yours very truly, 


The appeal in the letter enlisted the interest of the bureau and 
produced a desire for a careful investigation of the conditions com¬ 
plained of. Accordingly, the senior writer made a visit to the plant. 
It was the only factory in a small country town of about 100 inhabi¬ 
tants. Most of the employees, both men and women, came from the 
surrounding rural district. A stay of several days was made at 
the plant and various tests were conducted. 


















SANITARY CONTROL OF TOMATO-CANNING FACTORIES. 5 

Examination of the sorted tomato stock showed that although at 
times it was not above criticism, poor sorting probably was not the 
main source of the trouble. The irregularity of sorting might have 
been due in part to the poor lighting of the sorting table. Observa¬ 
tion of the method of cleaning the equipment at the end of the day’s 
run, however, showed that the various parts of the washers, con¬ 
veyors, cyclones, and pulp tanks were being only superficially cleaned. 
By reason of the method of construction or of the inaccessible loca¬ 
tion of the general equipment, some of its parts contained accumula¬ 
tions of tomato material fairly teeming with microorganisms. 

Three cyclones were in use in this factory. The pulp tanks of two 
of these cyclones were connected with that of the third by means of 
wooden pipes. Examination of the inside of these pipes showed a 
thick growth which was so heavy in molds as to give a count of 100 
per cent of the fields even after diluting 18 times. It was swarming 
with bacteria and yeasts and had an offensive, fetid odor. A count of 
bacteria gave over a billion per cubic centimeter. In other parts of 
the equipment the bacterial count w T ent to a billion and a half and 
nematode worms were found in numbers as high as 1,080 per cubic 
centimeter. Yeasts and spores were present in numbers up to 4,000 
per 1/60 cubic millimeter. 1 Examination under the microscope of a 
portion of the slimy coating showed it to be largely a mold growth 
with a mass of tomato debris and quantities of bacteria. Plate I 
show T s photomicrographs of the mold. A specimen of it was iden¬ 
tified 2 as composed largely of a type of mold called Oidium lactis. 
When grown under such conditions as found in this factory it as¬ 
sumes an elongated, feathery form which is quite distinctive in ap¬ 
pearance from that of the mold which grows on tomatoes. 

In the examination of some samples of tomato products this 
characteristic type of growth has been of practical use in indicating 
the existence of foul or dirty factory conditions. 

Inspection of the cleaning equipment of the factory showed that 
it was entirely inadequate. Too great reliance was being placed in 
the supposed efficiency of the steam hose, and there was lack of other 
proper cleaning apparatus. The cleaning process also was made 
more difficult because rough lumber had been used for flights on con¬ 
veyors, for paddles of the cyclones, and in other places. In addition 
to these difficulties some of the corners were inaccessible and poorly 
constructed. After suitable cleaning utensils were obtained and cer¬ 
tain changes made to facilitate the cleaning operation for the work- 

1 Under proper factory conditions it is possible to maintain the following maximum 
counts : Mold in 25 per cent of the microscopic fields ; yeasts and spores per 1/60 cubic 
millimeter, 25; bacteria per cubic centimeter, 25,000,000. (See U. S. Dept. Agr., Bur. 
Chem. Circ. 68, Tomato Ketchup under the Microscope, pp. 4, 5, 6.) 

2 By Dr. Charles Thom, Bureau of Chemistry. 




6 


BULLETIN 569, U. S. DEPARTMENT OP AGRICULTURE. 


men the high count was immediately lowered and remained low dur¬ 
ing the rest of the visit. 

Tests of the ketchup manufactured by this factory were made 
periodically during the stay and were distributed over 8 days. 
The first four tests were made prior to the general cleanup. The 
sample used in the fifth test was taken from the first batch of ketchup 
made after the cleaning was completed. About one-third of the 
molds in this sample were distinctly of the form which indicates 
dirty apparatus. They were the filaments dislodged during the 
cleaning process which had not been fully rinsed out during the wash¬ 
ing and hence were carried over in the first kettleful of the product. 
The last four tests were made during the next three days. 


Table 1 . —Microscopical examination of tomato ketchup before and after the 
installation of adequate cleaning equipment and methods. 


Test No. 

Per cent of 
fields 

with molds. 

Bacteria; 
million per 
cubic centi¬ 
meter. 

Yeasts and 
spores per 
1/60 cubic 
millimeter. 

1. 

45 

40 

65 

2. 

66 

60 

57 

3. 

64 

52 

52 

4. 

54 

43 

56 

Average before cleaning. 

57.2 

48.7 

57.5 

5. 

30 

9 

21 

6. 

16 

10 

15 

7. 

21 

10 

10 

8. 

15 

8 

7 

9.'. 

20 

7 

13 

Average after cleaning, excluding No. 5. 

18 

8.7 

11.2 


A study of Table 1 emphasizes the change in the counts between 
those made before and those made after cleaning, in that the counts 
have been reduced in the case of mold to about one-third and of 
bacteria and of yeasts and spores to about one-fifth. 

The question may arise in the minds of some readers as to whether 
the marked change shown in the counts might not have been the 
result of other influences than the cleaning. The only other change 
made was a minor one in the system of sorting. In Table 2 are 
given the results of efficiency-of-sorting tests. The method of making 
these tests is described in detail on page 18. The tests were made 
on the sorted and washed stock ready for the crusher and represent 
the approximate percentage of decay that was going into the finished 
product. The data in Table 2 show that the average percentage of 
decay during the first 5 days was 1 per cent, while during the last 
3 days (the after-cleaning period) it was 0.94 per cent. Obviously 
these figures are negligible in accounting for the marked changes 
observed in the counts. 

























SANITARY CONTROL OF TOMATO-CANNING FACTORIES. 


7 


Table 2.— Efficiency-of-sorting tests. 


Date. 


Sept. 22 
Do. 
Do. 
Sept. 23 
Sept. 24 
Do. 
Do. 
Do. 
Sept. 25 
Sept. 26 
Do. 


Hour of test. 

Percentage 
of decay. 

Date. 

Hour of test. 

Percentage 
of decay. 


2.20 

Sept. 26 

8.00 p. m_ 

10.15 p. m... 

0.37 

.93 

9.30 p. m_ 

1.60 

Do. 

10.45 p. m... 

1.50 

Sept. 29. 

10.00 a. m... 

1.70 

11.45 p. m... 

.81 

Do. 

5.30 p. m_ 

1.35 

9.15 a. m_ 

.87 

Do. 

8.00 p. m_ 

.50 

5.00 p. ra_ 

.50 

Do. 

8.30 p. m_ 

.43 

9.00 p. m_ 

.50 

Do. 

11.00p. ra... 

.75 

11.30p. m... 

1.10 

Sept. 30. 

10.30 a. m... 

.75 

10.00 p. m... 

.75 

Do. 

11.40 a. ra... 

.55 

11.45 p. ra... 

3.45 p. m_ 

1.10 

1.00 

Do. 

7.30 p. m_ 

1.00 


During the visit at the plant personal attention was given to the 
cleaning operations. Wherever possible without handicapping the 
operations of the factory, changes were made by which the apparatus 
was more easily and effectively reached for cleaning. In some cases 
wooden piping was changed, doors put in conveyors, pulp boxes made 
removable, and other changes were made by which the workmen 
could clean the various parts more quickly and efficiently. 

After these improvements had been made a change was noticed 
in the odor about the factory, especially when the steam hose was in 
use. The offensive, fetid odor, which had been noticeable in the ris¬ 
ing vapors whenever the steam hose was used, almost wholly dis¬ 
appeared, and in its place came the characteristic odor of fresh 
tomato pulp. 

Factory No. 2. 

A faulty sorting system was the cause of the high counts present 
in the product manufactured by another factory visited by the 
bureau’s representatives. This condition is more general than the 
existence of inadequate cleaning systems. 

It was brought to the attention of the Bureau of Chemistry 
that this factory was having difficulty in maintaining low counts on 
its products. On visiting the plant it was found that the tomatoes 
were dumped into a soaking tank, from which they were carried up 
by a conveyor and fed into a rotary washer, covered with a screen of 
too fine a mesh to allow its being as efficient in removing soft rot as 
is necessary. From this washer the tomatoes were fed to the sorting 
apron. This apron was so arranged that at intervals along its length 
a portion of the main stream of tomatoes was diverted through the 
scalding'boxes and out upon the peeling tables. Three sorters were 
working at the main sorting apron, but were so stationed that the 
tomatoes diverted to the first table received little or no sorting inspec¬ 
tion. Those for the second table received some attention, while those 
for the third had the greatest amount. The sorters also were trying 
to do trimming work. The result was that many spotted tomatoes 









































8 BULLETIN 569, U. S. DEPARTMENT OF AGRICULTURE. 

were not sorted out. Tests made for the percentage of rot in the 
sorted stock showed it to vary from about 0.1 per cent to over 2.5 per 
cent of decayed material. The apron was moving at a rate of 78 feet 
per minute. During the three days that tests were made at the plant 
several changes were instituted, among which were slowing down 
the rate of the apron, securing more women for the inspection 
service, and dividing them into squads. One squad did nothing but 
sort out the spotted tomatoes and put them in buckets the contents of 
•which were trimmed by the second set to remove the rot. Tests on 
the efficiency of sorting under the changed conditions gave a range 
of from no appreciable amount of rot to 1.3 per cent. 

Factory No. 3. 

A visit made to still another plant, some of the product of which 
had been condemned the previous season, showed that the tomatoes 
were passing through one of the washers and scalders at the rate of 
490 bushels per hour. Five young boys, between the ages of 13 and 
15, w T ere working at the sorting table. A test of the stock being 
fed to the sorting table gave about 16 per cent of rotten material. 
A similar test after sorting gave about 7.5 per cent. All the waste 
from the tomatoes removed at the peeling tables went into the 
cyclones for pulp making. 

WASHING. 

During the last few years various systems and devices have been 
tested under factory conditions and a mass of data has been collected 
bearing upon so many of the practical questions concerned in the 
production of a clean, sanitary product that it is proposed to discuss 
here the more important of these operations. 

Any one familiar with the canning industry must have noticed 
the changes that have taken place in recent years and the improve¬ 
ments that have been made in tomato-washing machinery. The choice 
of a proper washing system requires a knowledge of the specific 
conditions under which the system is to be operated in each case, 
since a system that works satisfactorily under one set of conditions 
may be inadequate elsewhere. 

In some parts of the country tomatoes are grown on a soil which 
has an abundance of sand in it and little clay. Tomatoes grown on 
such land are fairly readily cleaned by a good spraying apron 
washer. In other parts of the country the soil consists of a sticky 
clay loam, which clings so tenaciously as to make its removal by 
the spraying system alone very difficult. In such cases some sort 
of rubbing method is highly desirable. It is under such conditions 
that the rotary washers are efficient. Factory owners sometimes have 
been found who have been deceived as to the efficiency of their 


Bui. 569, U. S. Dept, of Agriculture 


Plate I 



BCHI887 

Fig. 1.—Mold from Slime on Insanitary Apparatus. (Magnified 100 Diameters.) 

Note the feathery character. 



BCHI894 


Fig. 2.—Mold from Slime on Insanitary Apparatus. (Magnified 300 Diameters.) 

















Bui. 569, U. S. Dept, of Agriculture. 


Plate 


BCH2326 


Tomato Turning Device Adapted to Simple Apron Sorting Table. 










SANITARY CONTROL OF TOMATO-CANNING FACTORIES. 9 

washers, because a thin coating of dirt on the skin of a tomato is 
less evident when the tomato is wet than when it is dry. Tomatoes 
that may appear fairly clean when wet may still show a thin, adher¬ 
ing coat of soil if allowed to dry. 

The principal types of washers in use are the following: (a) dump 
hopper; (b) worm (helicoid); (c) spray apron; (d) rotary; (e) 
paddle agitator; (/) air blast (geyser); (g) cascade. 

(a) The dump hopper is now used by only a few small packers. 
It has practically nothing to recommend it as a washer. 

(b) The old-style helicoid worm washers also are being replaced 
rapidly by the more modern types. 

( c) In the plain apron washer the tomatoes are carried on an open¬ 
work apron through an inclosed chamber in which are strong sprays 
that strike the tomatoes at various angles. This type of washer does 
satisfactory work provided the water pressure is high enough (some 
advise 100 pounds or more per square inch), and the soil on which 
the tomatoes are grown is not of a very sticky character. If a high 
pressure is used the apron washer assists materially in eliminating 
soft rot spots, although, of course, it should not be expected to do 
the work which properly belongs to the sorters. The type of nozzle 
used on these machines, however, offers opportunity for improve¬ 
ment. A nonclogging, flat spray form is much needed. The common 
spray form of nozzle usually employed does not deliver the force of 
the water evenly. Since the water is delivered in a circular form the 
tomatoes passing along the edges of the circles get the force of the 
stream for a longer time than those going through nearer the center. 
The orifice of emission of the water in this type is so narrow that it 
clogs quickly unless the water supply is very free from solid particles 
such as scale from the inside of the water pipes. Nozzles working 
on the impact principle do not seem to be so subject to these objections. 

( d ) The rotary washer consists of an inclined cylinder covered 
with a wire screen of 1-inch mesh. It is very commonly used and 
generally gives good results. Its advantages are that it rubs the 
tomatoes against each other, thus loosening the dirt, and it does the 
washing with a less expenditure of water than most of the other 
washers that give satisfactory results. Furthermore, it will remove 
some of the soft-rot tomatoes. 1 The principal objection urged against 
it is that the manner of its operation tends to crush some of the very 
ripe tomatoes, which may be sound but so ripe as to be tender. 

(e) In the paddle-agitator washer the tomatoes are dumped into 
a tank of water where they float and are agitated by slowly revolv¬ 
ing paddles, which cause the tomatoes to rub against each other, thus 
loosening the dirt. At the same time the tomatoes are worked along 
toward the conveyor, which removes them from the tank. As they 

100635°—Bull. 569—17-2 



10 BULLETIN 569, U. S. DEPARTMENT OF AGRICULTURE. 

are carried out they pass under water sprays which give them a final 
rinsing. v 

(/) The air-blast or geyser washer works on the same general 
principle as the preceding type, but produces the agitation by blasts 
of air entering the tank at or near the bottom. 

( g ) In the cascade washer the tomatoes are carried up a tight- 
bottomed conveyor inclined at an angle of 30° to 50°. Near the 
top are the inlets for water which emit a sufficient amount to produce 
a vigorous flow down over the ascending stream of tomatoes. Al¬ 
though it is a good rinser, it is not sufficient alone to remove 
thoroughly the sticky soil from the fruit. 

SORTING. 

ITS IMPORTANCE. 

A careful consideration of the causes of failure in making clean, 
sound, sanitary tomato products shows clearly that more difficulty is 
experienced in effecting satisfactory washing, prompt handling, and 
efficient sorting than in any of the other phases of the manufactur¬ 
ing process. Sorting is the most important of these operations, in 
which the judgment of the workman plays a considerable part. 
Satisfactory washing is largely a question of proper operation of a 
mechanical device. This may be said also of many of the other 
operations about the factory, but so far no mechanical contrivance 
for separating the decayed from the good parts of the tomatoes has 
been placed upon the market. This operation must still be performed 
principally by hand. Although some washers, if properly con¬ 
structed and operated, will assist in removing the badly soft-rotted 
tomatoes, efficient hand sorting must be employed if a uniformly 
good, sound product is to be obtained. 

Experience has shown that in factories where the tomatoes are 
used only for peeling stock and where all the trimmings are thrown 
away sorting is an unnecessary expense. In the making of pulp of 
any kind, however, efficient sorting is absolutely necessary. .Other¬ 
wise there can be no assurance of producing a uniformly sound 
product with low counts of microorganisms. 

The conditions observed and the results obtained in various fac¬ 
tories show that there is little, if any, choice between sorting the 
tomatoes before and after washing. Some of the best, as well as some 
of the poorest, results were obtained in factories where one or the 
other of these methods was employed. Approximately two-thirds 
of the plants visited during the seasons of 1915 and 1916 that did 
any sorting at all were using the wet method, and one-third the dry 
method. In order to remove clinging pieces of partially decayed 
tomatoes, the tomatoes always should be subjected to a washing or 


SANITARY CONTROL OF TOMATO-CANNING FACTORIES. 


11 


rinsing after sorting, even though the principal washing has been 
done before sorting. 

SORTING SYSTEMS. 

The various sorting systems in operation may be designated as 
(a) table, (b) simple apron, and (c) disfided apron. These systems 
are not kept entirely distinct, however, but frequently overlap in one 
particular or another. 

(a) In the typical table system the tomatoes are dumped upon a 
stationary table or sorted directly from the crate or basket. The 
tomatoes are picked out by the sorters who are stationed around the 
table, and after being examined are tossed into suitable containers, 
from which they are emptied from time to time into the washers. 
The decayed tomatoes or parts thereof are removed and rejected. 
One advantage of this system is that by examining the sorted stock 
in each container the efficiency of the individual sorters can be de¬ 
termined more readily than by any of the other systems. As a rule 
it is a fairly effective system, but usually is more expensive than any 
of the others. 

(b) In the simple apron conveyor system the tomatoes are placed 
upon a slowly moving, horizontal apron which carries them along 
in front of the sorters, who are supposed to remove all tomatoes that 
are entirely or partially decayed. Those not picked out constitute 
the stock finally used in the manufacturing process. By this system 
the tomatoes theoretically are subjected to as many inspections as 
there are sorters to the apron. With good sorters and where proper 
conditions of feed, rate of movement, and lighting are maintained this 
is practically true, but emphasis must be laid upon the observance of 
these details if satisfactory results are to be attained. 

Under normal conditions, where proper attention is given to details 
of feeding and lighting, the apron conveyor system has been found 
to yield as good results as any that has been devised. This is true 
for two reasons. In the first place, only those tomatoes that have 
decayed parts need to be picked up and taken out. During the last 
two seasons more than 100 tests were made on the unsorted stock in 
about 30 different factories in various parts of the tomato-producing 
sections east of the Mississippi Iiiver. These tests have shown that 
from 0.4 per cent to 81 per cent by number of the tomatoes were 
decayed, in whole or in part, to such an extent as to require trimming 
or total rejection. The average by number was about 25 per cent. 
This means that in an average bushel 1 of tomatoes 58 must be re¬ 
moved and rejected either in whole or in part. 

The second advantage of this system is that if one of the sorters is 
inexperienced or becomes a little lax in the work the fault is more 

1 The average number of tomatoes per bushel as determined by 174 tests made in 1016 
was 229. 




12 BULLETIN 569, U. S. DEPARTMENT OF AGRICULTURE. 

likely to be compensated for by the carefulness of the other sorters 
than in the case of any of the other systems. This, however, should 
not be used as an excuse for putting unreliable sorters on the apron. 

The width of aprons used varies greatly, ranging from 8 inches to 
4 feet. To get the best results the aprons should be narrow enough 
for the sorters to reach easily across the entire width. The most 
convenient and practicable width has been found to be from 18 to 20 
inches. 

Even greater variation is found in the rate of movement of the 
apron. Tests on the rate of speed in different plants showed a mini¬ 
mum rate as low as 16 feet per minute and a maximum as high as 
140 feet. The speed of the apron should be retarded sufficiently to 
permit careful observation of the individual tomatoes and to allow 
the sorters sufficient time to reach for and remove those with rotten 
spots. Observation of a large number of sorting aprons in operation 
has shown that it is impossible to obtain good results with a speed 
exceeding 25 feet per minute. 

(<?) In the divided-apron system the tomatoes are dumped upon a 
conveyor very similar in construction to the simple apron, but usually 
somewdiat wider. Over this conveyor a guide is suspended which 
divides the stream of tomatoes into two parts, one on each edge, 
and leaves also a vacant space through 4he center of the apron. The 
sorters stand beside the apron, pick out the good tomatoes, and toss 
them over into the middle section of the apron. All the tomatoes not 
thrown over into the middle section pass into the waste at the end 
of the machine. The good tomatoes pass on into washing or rinsing 
systems. A modification of this system is to remove the bad or 
spotted stock to the middle section from which they pass into the 
waste. 

Each tomato, theoretically, is subjected to a scrutinizing inspec¬ 
tion, but actually, when the sorters are inspecting rapidly, they will 
pick up some of the tomatoes and toss them into the center without 
taking the trouble to turn them over to see the underside. The fact 
that by this system all the tomatoes, both good and bad, must be 
actually handled contributes materially to the inefficiency of the sys¬ 
tem, as about 75 per cent of the entire stock are sound. It necessarily 
follows that, as a rule, a larger corps of sorters will be needed than in 
the simple apron system, where only tomatoes with decayed parts 
have to be handled. 

In constructing a sorting apron of either type the manufacturer’s 
first problem is to plan one that will meet his requirements as to 
capacity. A number of tests made on the area a bushel of tomatoes 
will cover when laid out in a layer one tomato deep showed that, in 
general, the larger the tomatoes were the smaller was the area cov¬ 
ered. The tests made showed a variation of from approximately 7 to 


SANITARY CONTROL OF TOMATO-CANNING FACTORIES. 13 

12J square feet per bushel, with an average of about 9J. As the to¬ 
matoes should be fed onto the apron so as to leave at least one-half of 
the space uncovered, a space of about 18J square feet should be pro¬ 
vided for each bushel. This would mean that a sorting apron 18 
inches wide and moving at the rate of 25 feet per minute would have 
a capacity of about 120 bushels per hour and when handling average 
stock would require the services of six efficient sorters. On this basis 
a separate sorting apron would be required for each 1,200 bushels 
handled per 10-hour day. Such an arrangement provides for the 
most efficient utilization of equipment. In some factories visited the 
arrangement was so poorly planned that the apron was running ten 
times faster than was necessary for handling the volume of stock. 
In other factories the tomatoes were run through at from five to six 
times the normal capacity of the machine and the number of sorters 
was insufficient to handle them under proper conditions. 

SORTING SYSTEMS THAT HAVE FAILED. 

In the past the practice of making pulp from peeling-table waste 
was not uncommon. Much of this pulp, in a more or less concen¬ 
trated condition, was placed in barrels and disposed of for making 
cheap ketchup. The careless methods employed resulted in many 
condemnations of the product under the Federal Food and Drugs 
Act because the product was decomposed, in whole or in part. As a 
result of the Government’s campaign against adulterated tomato 
pulp, some of the evils of the practice have abated. 

The pulp commonly used for low-grade ketchups sold at from 75 
cents to $2.50 per barrel, most of it selling for from $1 to $1.75. At 
these prices the manufacturer received only about enough to pay for 
the disposal of the waste which otherwise was an item of expense. 
When it is realized that the stock from which tomato pulp is made 
may contain 20 per cent of rotten tomatoes and yet not give to the 
finished product such plain evidences of their presence as to be de¬ 
tected by the average consumer, it is easy to understand the tempta¬ 
tion and opportunity for negligence and carelessness in the manufac¬ 
ture of the product. 

Some firms, by modifying their methods of manufacture, have been 
attempting to produce from trimmings an article which would be 
satisfactory under pure-food laws, but only a few have been suc¬ 
cessful, and these only in part. An examination of the prosecutions 
brought against adulterated tomato products during the last six years 
will show that most of these products were made from trimming 
stock. A recognition of these facts has raised the question whether 
it is possible to make a satisfactory pulp from the trimmings. It is 
possible to do this, but the added labor required makes it doubtful 
whether it is profitable. As the tomatoes must be sorted and handled 


14 BULLETIN 569, U. S. DEPARTMENT OF AGRICULTURE. 

with unusual care if the trimmings are to be used for pulp, about 
one-eighth as many sorters as peelers must be employed. 

Various methods have been tried unsuccessfully in different plants 
in the hope of avoiding the labor and expense involved in a thorough 
sorting of the stock before it passes to the peeling tables. An account 
of the least successful methods follows. 

One method consists in furnishing each peeler with two buckets, 
one for sound trimmings, the other for decayed portions. The 
peelers are paid only for the peeled tomatoes. Hence, very little 
or no attention is given to sorting the good from the bad portions 
of the trimmings. Even if the sorting were done carefully there 
would still be the objection that the good portions had been con¬ 
taminated by contact with the partially rotten portions during the 
handling after scalding and before peeling. 

Another method tried by some manufacturers is to rinse the trim¬ 
mings themselves. This is unsatisfactory for the following reasons: 
The washing results in a great loss of material; the trimmings on 
account of their bulk can not be washed effectively; and no washing 
system has been devised which will remove certain types of decay. 

A third method is to inspect the trimmings after they leave the 
peeling tables and to remove the bad portions. A small proportion 
can be picked out in this manner, but the amount is so small that the 
system is of very slight value. After a large number of cut pieces, 
such as occur in trimmings, have been dumped together it is a 
physical impossibility to sort out any but the more solid portions, 
such as large pieces and those of dry or black rot. The pieces of 
soft rot become mashed and contaminate the whole mass and can 
not be removed. 

UNIFORMITY AND RATE OF FEEDING. 

The rate at which the tomatoes are fed upon the apron is an im¬ 
portant factor in the efficiency of sorting. Tomatoes frequently are 
fed so irregularly that it is impossible to obtain good results. 

Observations were taken at several plants for the purpose of 
determining what variation occurs in feeding the tomatoes to the 
sorting apron. The data from one of these inspections are given in 
Table 3. 


Table 3. —Variation in rate of clumping tomatoes into the washer. 


Time. 

Bushels. 

Time. 

0 

Bushels. 

First 2 minutes. 

8 

Next 6 minutes . 

n 

Next 3 minutes. 

0 

Next lj minutes 

u 

A 

Next 2 minutes. 

9 

Next lj minutes 

A 

Next 1 minute. 

0 

Next 1 minute. 

u 

A 

Next 1 minute. 

4 

Next 9 minutes 

0 






























SANITARY CONTROL OF TOMATO-CANNING FACTORIES. 


15 


This series of observations, which extended over a continuous 
period of 28 minutes, shows a variation of from 0 to 4J bushels per 
minute. The table shows that during the 28 minutes there were 
five periods of from 1 to 9 minutes each (aggregating a total of 19^ 
minutes) during which no tomatoes at all were dumped into the 
washer. From the washer the tomatoes were removed by a conveyor 
to the sorting apron. This tended to equalize the variation some¬ 
what, but there was still great irregularity as the tomatoes were 
delivered finally for sorting. Although the average rate was only 
about 66 bushels per hour, there were periods when the observed 
rate amounted to 270. Such variation makes it practically impossible 
to obtain uniform results in sorting. 

In dumping directly on the sorting apron the workmen often 
become careless and the tomatoes pass to the sorters in piles inter¬ 
spersed with vacant areas. In some plants one of the workmen is 
assigned to the task of regulating the rate at which the tomatoes are 
fed from the dumping board to the apron, but even this is not wholly 
satisfactory. An attempt has been made to overcome this difficulty 
by providing a mechanical device in the form of a feeding hopper, 
and although this device has not been tested thoroughly, it gives 
promise of relief. This feeding hopper consists of a short conveyor 
18 inches wide and about 42 inches long, inclosed at the sides by 
boards extending 6 inches above the apron. It is so regulated that it 
travels 3 feet per minute. The conveyor or hopper thus made is kept 
rounding full and so placed as to deliver the tomatoes to the sorting 
apron with as little drop as possible. With these specifications as 
to size and speed, such a feeder, if kept full, will deliver 120 bushels 
of tomatoes per hour to the sorting apron at a regular speed. This 
is about the amount that can be handled satisfactorily on a sorting 
apron operated by 6 good sorters. Although this device as yet has 
been tested only in an experimental way under factory conditions, 
the results appear encouraging. 

TURNING DEVICES. 


For good sorting it is important that during the process all sides 
of each tomato be subjected to inspection. In 1911 the writer pointed 
out 1 the desirability of a mechanical device to turn the tomatoes 
over while they are on the apron. Some firms manufacturing ma¬ 
chinery and several packers have undertaken to accomplish this in 
various ways. Of the forms applicable to the simple apron a certain 
device used in one plant has such merit that a description of it should 
prove valuable. Its simplicity, cheapness, and effectiveness, together 

1 Tomato Ketchup under the Microscope. U. S. Dept. Agr., Bur. Chem. Circ. 68, 

Feb. 13. 1911. 




16 BULLETIN 569, U. S. DEPARTMENT OP AGRICULTURE. 

with the fact that it can be made by the mechanic of almost any plant, 
are important points in its favor. 

For an apron 18 inches wide, 14 pieces of f-inch iron pipe (1 inch 
outside) were cut, each piece about T inches long. About one-half 
inch from one end of each piece a hole was drilled through the pipe 
large enough to permit of the pipes being strung on a J-inch steel rod. 
In order to insure freedom of movement a thin washer was placed 
between each pipe and the one next to it. The whole set was then 
suspended by means of the steel rod across the sorting apron with 
the lower ends one-half inch above the apron. A back-stop rod is put 
in behind the set to prevent the pipes from swinging back past the 
center. This was found necessary to prevent them from swinging so 
far back as to strike and gouge the oncoming tomatoes. Plate II 
shows a sorting apron fitted with three sets of pipes, thus allowing 
for one set between each pair of sorters. In operation the weight of 
the pipes is sufficient to roll the tomatoes over as they pass under. 

In order to obtain satisfactory operation it is most important that 
the tomatoes do not cover more than 50 per cent of the apron area, 
otherwise they do not have room to turn properly. A test at one 
plant showed that TO to 80 per cent of the tomatoes were turned each 
time they passed, under a set of the pipes. It was found also that 
this turning device worked better on the open metal apron than on 
the canvas or rubber type, owing to the fact that the tomatoes slipped 
badly on aprons made of canvas or rubber. 

LIGHTING THE SORTING TABLES. 

The matter of providing suitable lighting for efficient sorting often 
has been neglected. In all too many instances there are no top lights, 
no provision is made for artificial lighting on dull days, or the 
workmen stand in their own light or labor under similar difficulties. 
Sorting requires quick observation and action and the workmen 
should have every possible advantage. Certain manufacturers have 
expressed gratification on noting the increased facility with which 
the tomatoes on the apron could be examined after their plants had 
been lighted properly. 

The tomato-packing season comes at a time of the year when many 
days are cloudy. Hence, in planning an equipment provision always 
should be made to meet the most unfavorable conditions. The most 
desirable form of light is top light. This usually can be obtained at 
small expense by putting in a skylight. Where this is impracticable, 
two 100-watt electric lights with good white reflectors suspended 4 
feet over each table give satisfactory light. In order to make pro¬ 
vision for dark days it is desirable to have some such form of arti¬ 
ficial lighting, even when the sorting room has a skylight. The 


SANITARY CONTROL OF TOMATO-CANNING FACTORIES. 17 

lighting should be so arranged that the shadows of the workmen do 
not fall upon the table. The walls and ceiling of the sorting room or 
shed should be painted white or whitewashed. 

SELECTION OF SORTERS. 

Greater care should be exercised in the selection of sorters than in 
the selection of any of the other laborers connected with the manu¬ 
facture of tomato products. Some packers apparently have made 
the mistake of thinking that anyone who was not definitely employed 
elsewhere was good enough for sorting. Sorters, however, should be 
men or women (women usually have proved more satisfactory) old 
enough to be responsible and dependable, young enough to be still 
active and energetic. Young people not thoroughly responsible should 
under no conditions be intrusted w4th this important work. More 
harm can be done by one or two careless persons at the sorting apron 
than almost anywhere else in the plant. 

The work is of a kind that requires perhaps closer attention 
and application than any other work about the plant, and might well 
be called “ skilled labor,” since efficiency in producing the best results 
comes from practical experience. Because of the close attention 
required of the workers it is one of the’most fatiguing operations 
about the plant, and it is believed that a small bonus per hour to the 
persons selected to do this work would serve as an incentive to more 
painstaking work. In some factories visited, however, the sorters 
were paid only half or two-thirds as much per day as the peelers. 
Such shortsightedness in factory management is certain to lead to 
dissatisfaction and carelessness. 

Because of the fatiguing character of the work, it would be wise 
where feasible to work the sorters in shifts of not over three hours 
each. The sorting should be superintended by a person who has 
proved himself highly efficient in that line of work or by one who is 
alert and has a discriminating mind and is able to handle workmen 
tactfully. 

Where the simple apron system is used it is best to place the most 
efficient sorters last, in order that the final inspection may be made 
the most critical. 

VOLUME SORTED. 

The volume of tomatoes handled by one sorter is dependent upon 
several factors, among which the most important are the condition 
of the tomatoes, the system of sorting used, and the efficiency and 
experience of the sorter. With average stock it is impracticable to 
get good results by the table system if the tomatoes are delivered at 
a rate of more than 5 to 8 bushels per sorter per hour. With the 


t 


18 BULLETIN 569, U. S. DEPARTMENT OF AGRICULTURE. 

apron systems 20 to 25 bushels per sorter per hour have been about 
the practical limit for obtaining uniformly good results. Packers 
heretofore have given this point far too little consideration. It has. 
been observed in some factories that the tomatoes were passing 
through at the rate of 200 bushels per sorter per hour. It is quite 
evident that little or no benefit can result from the operation of a 
sorting table under such conditions. 

In order to impress upon producers the importance of handling the 
crop properly, some packers have put into operation a “ loss-off ” 
system by which they pay for the tomatoes on the basis of the sound 
tomatoes, allowing the presence of only a nominal proportion of 
spotted ones. 

EFFICIENCY OF SORTING. 


Practically all plants have some kind of sorting system, but ex¬ 
periments and observations in different plants show a wide variation 



o.e 

















































































* u/v&o^r/ro 































V 





















































■ 

























X 

X 





















m 














»■ 

















































« 




*-—% 







J 





1 






V 

A 



s 

'■*—. 



V 

A 





/ 

V 




l 






k 

I 


Fig. 1 . —Efficiency sorting chart. Each cross or dot represents the result of an indi¬ 
vidual test and indicates the percentage of rot found. 


in the efficiency of such systems. In some plants the sorting is done 
effectively, while in others the work is performed so poorly as to be 
practically valueless. 

In order to obtain a numerical expression of the efficiency of sort¬ 
ing, the following method was employed: To secure the samples 
small portions of the stock were taken from the stream at intervals 
of about 15 seconds until a total sample of 20 to 40 pounds had 
been secured. The tomatoes in the composite sample were then 
examined critically for decayed portions. The objectionable parts 
were cut out, weighed, and their percentage calculated. Tests 
made under a variety of conditions in different factories showed 
that with proper equipment and control the percentage of decay 
can be maintained at 1 per cent or less. For purposes of com- 




















































SANITARY CONTROL OF TOMATO-CANNING FACTORIES. 19 

parison tests also were made on some of the unsorted stock. The 
results of the tests from a few typical plants are shown graphically 
in figure 1. The tests at each factory are plotted in the order made, 
but they were not made at equal intervals. 

Factory No. 1 illustrates a case where the stock used was of very 
poor quality but, owing to the excellence of the sorting and washing 
systems, the decay was kept down to an average of 0.8 per cent, 
although two or three of the tests ran rather high. 

Factory No. 2, which had experienced trouble in producing a sani¬ 
tary product, adopted in 1916 a s}^stem of sorting and washing that 
very much improved the character of the product. In this case the 
average of the tests made for amount of rot was 0.5 per cent, with 
one test running up to the high point—for sorted stock—of 1.7 per 
cent. 

The table system of sorting was being followed at factory No. 3. 
The work, however, was done so ineffectively that tests on the sorted 
stock showed about 1.4 per cent of rot as against about 1.5 per cent 
for the unsorted, so that there was practically no improvement. The 
average amount of rot present was one and three-quarters times 
as much as in factory No. 1, although the condition of the unsorted 
stock at factory No. 1 was fourteen times as bad as at factory No. 3. 

At plant No. 4 the conditions as to sorting were found in 1910 to 
be very unsatisfactory. Since that time extensive experiments have 
been made, until in 1916 the improvement shown in the chart was 
observed. The average of the seven tests made on two days was 
about 0.5 per cent. 

The chart also shows the result of tests made during three days 
at factory No. 5. At the beginning of the experiment the plant had 
a number of serious defects in its sorting system. Later, several 
changes were made in the system and the factory was operated on a 
more approved method with striking results. The point when the 
changes were adopted is shown in figure 1 by the letter A. The 
average of the tests on the sorted stock prior to A was 1.26 per cent 
of rot; of the tests made subsequently, only 0.28 per cent. 

Data collected in many factories showed that in samples of un- 
sorted stock examined the percentage by weight of rotten material 
varied from practically nothing to over 30 per cent, while the aver¬ 
age in the whole series was about 5.5 per cent. The percentage of 
rot in the sorted stock (including the badly sorted as well as the 
thoroughly sorted) varied from practically zero to over 7 per cent, 
while the average was about 1J per cent. 

The percentage of rot by number was also determined during the 
season of 1916 in most places in addition to the percentage by weight. 
Although not so reliable as the determination by weight, it does at 


20 BULLETIN 569, U. S. DEPARTMENT OF AGRICULTURE. 

times serve as a quick, rough method of arriving at a knowledge of 
the character of the stock. 

The data obtained show that on unsorted stock the percentage by 
number of tomatoes with rotten spots is approximately six times 
as great as the percentage by weight of decayed material. In seek¬ 
ing to estimate the proportion of decay in this manner, however, in 
the practical testing of stock the results can be regarded only as a 
rough approximation, since the variation in individual cases is very 
wide, ranging from a ratio of about 2 in some cases to 15, and in a 
few instances even higher than this. If this method is to be used in 
a practical way it should be used only where the percentage by num¬ 
ber of decayed tomatoes does not exceed about 15, since even in that 
event it would indicate very roughly 2^ per cent of rot by weight. 
The factor, as a rule, becomes smaller as the percentages increase, 
owing to the relatively higher proportion of tomatoes with large 
spots. In the samples of sorted stock the average ratio of percentage 
of spotted tomatoes by number to percentage of rot by weight was 
about 10 to 1. 

These relationships indicate that the rotten or spotted condition 
in unsorted stock averaged one-sixth of the mass of the tomato in 
which found, while in the sorted stock it averaged about one-tenth 
of the mass. 

COST OF SORTING. 

The question of the cost of sorting is important to the manufac¬ 
turer. The wage commonly paid for this type of labor is about 15 
cents per hour. The output by the table system of sorting ranges 
from 5 to 8 bushels per sorter-hour. Hence, the minimum cost by 
this system is about 2 to 3 cents per bushel. The investment for 
sorting equipment in this system is practically nothing. 

By the apron system, good effective sorting can be made at the 
rate of 20 bushels per sorter-hour, thus reducing the labor cost to 
about three-fourths of a cent per bushel. This is simply for the 
removal of the tomatoes that are more or less decayed and that must 
be trimmed if any part is to be retained for use. The trimming 
process itself is believed to be usually a self-paying proposition. 

TRIMMING. 

Some packers have been observed to discard the whole of any 
tomato that showed a decayed spot. Tests made under factory con¬ 
ditions, however, prove that this is a wasteful practice, since the 
average amount of decay on unsorted stock is only about one-sixth 
of the whole tomato. Hence, to remove absolutely all traces of decay 
from each tomato, usually less than one-third of the tomato would 
need to be cut out. The remainder of the tomato would be entirely 


SANITARY CONTROL OF TOMATO-CANNING FACTORIES. 21 

suitable for use. In the apron system, however, it is strongly advised 
that if trimming is to be practiced it be done by a different set of 
employees from those who do the sorting, for if the sorter is required 
both to sort and trim at the same time his attention will become 
divided and he will pass many bad tomatoes. 

Tests made at one plant where the work of sorting and trimming 
was done by two sets of workers showed that one trimmer reclaimed 
43J pounds of good stock in 25 minutes, or 104.4 pounds per hour. 
At the price then paid for tomatoes the quantity that was saved com¬ 
pensated for more than one-third of the expense of the efficient 
sorting and trimming being done at the plant. 

PULPING. 

The pulping systems in use may be classified as (a) cold and ( b) 
hot. By the cold system the tomatoes are not cooked, but are put 
through the cyclones before or after passing through a chopping or 
crushing device. This is the usual system followed in making pulp 
from trimmings, although the scalding of the tomatoes for peeling 
slightly cooks the surface tissues. When the stock is scalded for 
peeling, and occasionally for whole-tomato pulp, the light cooking 
makes possible a cleaner separation of the pulp from the skin than 
is secured by the typical cold method. 

By the hot system the tomatoes are partially cooked before going 
to the cyclone. This cooking undoubtedly gives a larger yield of 
pulp from the stock and tends to arrest or decrease the growth of 
microorganisms. Some manufacturers claim that they obtain a 
redder product by the cold than by the hot system, but the observa¬ 
tions of the bureau seem to indicate no marked difference in the color 
of the product that may be attributed fairly to either system. 

PULP-MAKING SYSTEMS. 

The only places where the making of satisfactory trimming pulp 
has come under the observation of the department are those factories 
in which the tomatoes for canning were very carefully sorted before 
going to the peeling tables. This is done preferably before the to¬ 
matoes have been scalded, as after scalding they are too hot to be 
handled with any comfort, even when given the customary “ chilling.” 

Some canners had the sorting done by men who had some other 
duties around the scalder or washer. This, however, is very unde¬ 
sirable, for if satisfactory results are to be obtained it is important 
that even more critical sorting be maintained than in the making 
of whole-tomato ketchup or pulp. This necessity for care is equally 
applicable to all the details of pulp making, such as method, speed of 
apron, capacity, personnel, and efficiency of the sorters, and prompt- 


22 


BULLETIN 569, U. S. DEPARTMENT OF AGRICULTURE. 


ness in handling the product. When proper attention is given to these 
details a satisfactory product can be obtained, but it is in the exercise 
of the care required that many packers have failed. 

Why should the manufacturer desire to turn his trimming waste 
into pulp? Tests made at various factories have shown that 30 per 
cent or more of the weight of the tomatoes as received at the fac¬ 
tory goes into the waste known as trimmings. An examination of 

ordinary trimmings 
shows them to consist 
of: (a) the skins from 
peeled tomatoes; (b) 
the stems and coarser 
part of the cores from 
around the stem end of 
the fruit; (c) the de¬ 
cayed and rotten parts 
cut out from the other¬ 
wise good fruit; ( d ) 
tomatoes wholly de¬ 
cayed; and (e) small 
tomatoes, and others 



of such size or shape 
that it would be un¬ 
profitable to skin them. 
If the trimmings were 
in good, clean condi¬ 
tion, it is probable that 
no serious objection 
could be raised against 
pulp made from (a), 
(6), and (<?), provided 
the packages were 
properly labeled to in¬ 
dicate the origin of 
the product. 

Figure 2 shows 
graphically a system 
for manufacturing 
pulp fro m tomato 
trimmings. Although when properly handled such a system should 
give a satisfactory product, it is complicated, and the extra labor 
required in the use of trimmings in the pulp may not in average 
seasons be compensated by the value of the product resulting. 

Because of the fact that a considerable part of the waste comes 
from small tomatoes which the peelers find it unprofitable to skin, 


Fig. 2.—Diagram of system for the manufacture 
tomato pulp from sound tomato trimmings. 


of 





















































SANITARY CONTROL OF TOMATO-CANNING FACTORIES. 


23 


it has been suggested by some manufacturers that they might, at the 
start, pass their stock over a mechanical grader to remove all the 
small tomatoes before the peeling stock goes to the scalder. These 
small tomatoes could then be put through the proper processes for 
pulp making while the regular trimmings from the peeling tables 
would be totally discarded. Figure 3 is a graphic representation of 
such a system. Although this system appears reasonable and has 
been tested out by a few firms, sufficient data are not yet available 
to show its practicability as a commercial proposition. It is much 
simpler than the sys¬ 
tem shown in figure 
2 and yet provides 
for the utilization of 
a large part of the 
sound portions usu¬ 
ally lost in the trim¬ 
mings. 



PROMPTNESS IN 
HANDLING 
STOCK. 

The attention of 
manufacturers has 
been called repeat¬ 
edly to the impor¬ 
tance of the prompt 
handling of tomato 
stock, especially of 
the pulp after the 
sorting, washing, 
and pulping proc¬ 
esses have been 
started. One of the 
greatest objections to 
the old “ gravity 
system ” is the de¬ 
lay occasioned at a stage when conditions are most favorable for 
rapid multiplication of the organisms. In this system stock that 
otherwise might be satisfactory is held for a period of time under 
conditions nearly ideal for rapid growth of organisms, especially 
bacteria and yeasts. 

By the gravity method the stock before pulping usually is warmed 
more or less, according to the fancy of the manufacturer. After pass- 


Fig. 3.—Diagram of system for the manufacture of tomato 
pulp from small tomatoes. 










































24 BULLETIN 569, U. S. DEPARTMENT OF AGRICULTURE. 

ing the cyclone the pulp is allowed to stand in a tank or vat. In half 
an hour or so the clear juice begins to separate from the fibrous 
cellular portions, which tend to rise, owing to the entangled gas. 
When this stage is reached a stopcock or bung near the bottom of the 
vat is “cracked” and the juice drawn off. Meanwhile, more pulp 
usually is added. In this way the pulp is held for varying lengths of 
time up to half a day or more, which obviously allows some spoilage 
to take place. Another objectionable feature is that a large part 
of the soluble solids, which contribute much to the flavor of properly 
made products, is thrown away. The rapid decline in the use of the 
gravity method during the last few years, therefore, marks a decided 
advance in the manufacture of tomato products. 

Manufacturers should seek to reduce to a minimum the time re¬ 
quired to carry the product through from basket to bottle or can. 
The slogan “An hour from basket to bottle” expresses a degree of 
efficiency which should be striven for by every manufacturer and 
which already is being attained in some factories throughout the 
country. 

CLEANLINESS IN THE FACTORY. 

ITS IMPORTANCE. 

A knowledge of the conditions favorable for growth of micro¬ 
organisms serves to emphasize the great importance of cleanliness 
about a canning factory. To secure normal growth there must be 
first the spore or a portion of the vegetative part of the organism 
to start the infection. Then for its development or multiplication 
there must be a suitable food supply, moisture, and a certain amount 
of heat. The rate of growth varies for different organisms and is 
influenced greatly by the nature of the food supply and the degree 
of heat. 

One of the most persistent species of mold occurring around 
tomato-canning factories is that identified as Oidium laetis (Plate I). 
Molds growing on apparatus impart to it a slippery feel, very differ¬ 
ent from that which characterizes clean apparatus. A deposit of 
more or less cheesy consistency usually can be scraped from apparatus 
having such a feel. 

Mold will grow sometimes in many unexpected places, such as on 
metal and wood conveyors, on cyclone paddles, and in similar places. 
As its presence always indicates lack of thoroughness in cleaning, it 
will be seen that proper cleaning is of vital importance if a sanitary 
condition is to be maintained in the plant. By proper forethought 
in planning and equipping a factory the difficulties in keeping it 
clean can be reduced greatly. It frequently happens that in devising, 
selecting, and installing factory equipment too little thought is 


SANITARY CONTROL OF TOMATO-CANNING FACTORIES. 25 

expended in seeing that all parts are so built and placed as to be 
easily accessible for cleaning. For instance, cyclones which as de¬ 
signed by the makers could be readily cleaned, have sometimes been 
so installed that effective cleaning was almost impossible. All parts 
should be accessible for scrubbing, as hose or steam alone can not be 
depended upon. Care should be exercised to avoid as far as possible 
all unnecessary angles resulting from careless lapping or matching 
of parts. Rounded corners can be used at times to great advantage. 

THE NECESSARY EQUIPMENT. 

An inspection of the equipment of some plants often discloses a 
striking lack of cleaning apparatus, such as water taps, hose, scrub 
brushes, and brooms. There should be adequate hose facilities for 
quickly and effectively flushing out machinery and floors. Three or 
four lines of hose and connections conveniently placed are none too 
many for an average canning factory. Many factories now have 
water connections by faucet or short hose within ready reach of each 
peeler. Such an arrangement allows each worker to clean quickly 
her own part of the equipment. 

A steam hose also should be available. Some persons, however, 
have been inclined to put too much faith in the efficacy of the steam 
hose. If intelligently used on machinery that already has been 
properly scrubbed, it does excellent work in cleaning out loose ma¬ 
terial from crevices and in sterilizing and heating the metal parts 
so as to produce quick drying. For cutting out mold and slime on 
broad surfaces, however, a steam hose usually is insufficient. The 
average workman is likely to use it for too short a time and on too 
limited an area. 

An ample supply of brushes—not simply one or two—should be 
readily available. The water-soaked brooms used in some factories 
should be replaced by stable brushes with stiff, split-rattan or steel- 
wire bristles. For cleaning wet floors such brushes are easier to use 
than brooms and are far more effective, as they cut the dirt and slime. 
The hand brushes also should be of some stiff material which will not, 
after being used a few times, become water-logged and mat down 
and simply glide over the surface without loosening the slime. 
Painter’s triangles for reaching into and scraping difficult corners 
also have been found helpful. One or more flashlights would be of 
service for inspection and for working in obscure places. 

USE OF EQUIPMENT. 

After an adequate cleaning equipment has been installed a well- 
systematized plan of operation must be put into effect. Each work¬ 
man should have an active part in this system. The most effective 
method for cleaning the floors is to assign three or four active men to 


26 BULLETIN 569, U. S. DEPARTMENT OP AGRICULTURE. 

the task. One of these men handles the hose, directing the water 
where needed; the others loosen the dirt with stable brushes and give 
the final cleaning. In this way a large area can be cleaned quickly 
and effectively. 

At one plant of moderate size such a plan was observed under 
operation. The periods immediately preceding luncheon and at the 
close of the working day were set aside for cleaning. The employees 
worked with such a degree of system that in 10 minutes the sorting 
table, washing and scalding machines, peeling tables, buckets, filling 
machines, cyclones, finishers, and floors were given a thorough clean¬ 
ing. The reasons for this efficiency were that plenty of water was 
available, the apparatus was located conveniently, and each person had 
his or her part of the work to perform. Each woman cleaned her 
buckets and pans and her part of the peeling table, the sorters cleaned 
the sorting table, and washing and scalding outfits, while the pulp 
men were held accountable for the cleaning of their equipment. At 
the same time those working at the filling and capping machines 
cleaned their respective outfits. While these operations were going on 
several men had started flushing and scrubbing the floors at places 
where they would least interfere with the other, emploj^ees, and as 
soon as the others had finished their cleaning the remainder of the 
floor was finished. The drains were so located as to help facilitate the 
entire operation. 

If any part of the room had not been properly cleaned it was an 
easy matter to fix the responsibility, since each person had a definite 
work to perform. 

Apparatus if well cleaned should, when wet, be free from any 
slippery or slimy feel and when scraped should not yield a cheesy 
deposit. At the close of the day’s work the equipment after being 
cleaned should be left in such position as to permit of ready drainage, 
ventilation, and drying. These precautions will tend to check the 
growth of microorganisms. Pails, pans, and buckets should not be 
stacked, as is frequently done, and the cyclones, as well as the tanks 
and vats, should be left open. 

PSYCHOLOGY OF CLEANLINESS. 

The old adage “ Like begets like ” is applicable in factories as well 
as elsewhere. Where there is intelligent and tactful demand for 
cleanliness on the part of the factory management there is certain 
to be a conscious or unconscious response on the part of the em¬ 
ployees. A workman has small incentive to adopt cleanly methods, 
however, if filthy, slovenly, or unsystematic conditions about the 
factory are the rule. Workmen usually prefer employment in clean 
surroundings. One factory owner who maintained his plant in good 


SANITARY CONTROL OP TOMATO-CANNING FACTORIES. 27 

condition reported that instead of having a shortage of suitable help 
he had on file a waiting list which enabled him to fill any vacancies 
on his force with selected help, although some factories near by were 
finding it impossible to get sufficient help. 

The factory might Avell be regarded as a cooperative institution 
and the employees made to feel that its welfare is a part of their 
personal concern. Clean dressing rooms, clean, sanitary toilets, and 
simple provisions for caring for emergency accidents will be ap¬ 
preciated by nearly all the employees. But in order to attain such 
an esprit de corps the superintendent or manager himself must be 
foremost in planning and systematizing the work of cleaning, which 
must be begun at the opening of the season and tactfully enforced 
throughout the entire season if it is to prove successful. 

LABORATORY CONTROL. 

From the standpoint of law enforcement, laboratory methods of 
examination are necessary, since there is no other way by which the 
officials on whom rests the responsibility for enforcing the law can 
judge correctly whether the product complies with the law’s require¬ 
ments. Without the check afforded by laboratory methods the 
product of insanitary factories would come into open competition 
with sound and good products, and in such condition that the con¬ 
sumer usually would be unable to detect its true, offensive nature. 

Large manufacturers who have analysts thoroughly well-trained 
in microscopical methods have also found laboratory supervision of 
great value as a means of checking the work of their sorters and 
superintendents. The fact that the character of their work can be 
determined from an examination of the finished product is a strong 
incentive toward inducing employees to exercise a greater degree of 
care in the various details of manufacture. It is well also for the 
analvst to check his work from time to time with that of other reliable 
analysts in order to keep his own operations in agreement with those 
of others in the same line. No conscientious analyst would undertake 
to do careful analytical work for a manufacturer before he had 
proved himself reliable through experience with the product and 
through checking his findings with those of other analysts, known 
to be reliable. 

The manufacturers also may test the ability of their analysts by 
submitting to them sterilized portions of the same sample at dif¬ 
ferent times under different identifying marks. It is of the utmost 
importance, however, that the samples be exact duplicates, for if 
they have not been taken from the same batch after thorough mixing 
and then kept under sterile conditions the results are utterly worth¬ 
less for purposes of comparison. It is the writer’s belief that some 


28 BULLETIN 569, U. S. DEPARTMENT OF AGRICULTURE. 

of our food manufacturers view this question of laboratory control 
from an entirely wrong angle. It is thought that there are some 
manufacturers who use it simply as a means of trying to get their 
goods to “ pass inspection.” Instead of seeking to make the best 
product possible the temptation is to make a product just good 
enough to escape adverse action on the part of the food-control 
official who examines it. It is not to be inferred from this state¬ 
ment that any large number of American manufacturers consciously 
take this attitude, but such a result is always likely to follow^ when¬ 
ever a definite standard for a product is proposed in any line of busi¬ 
ness. 

The Department of Agriculture desires to emphasize in this bulle¬ 
tin the supreme importance of certain methods and elementary steps 
in manufacturing as prerequisites in the production of sanitary goods. 
As the analyst for a firm once said, “If the objectionable material 
has been kept out during manufacture, no laboratory test will find 
it present when the finished product is in the bottle.” If proper 
attention has been given to the necessary details of manufacture, 
no laboratory examination should be needed, while, on the other 
hand, if such details have been slighted, no amount of laboratory 
work can correct the evil and make the product one that can be 
classed as sanitary and worthy to be put on the market for con¬ 
sumption. 

SUMMARY. 

In recent years great changes have taken place in the methods of 
manufacturing tomato products, such as the abandonment of the 
u gravity system ” and of storage in barrels, and the introduction of 
careful sorting systems. 

Many manufacturers believe their plants are sanitary and do not 
know why their products show impurities. Examination of several 
factories showed defective methods of cleaning the apparatus; in 
other places inadequate sorting methods were found responsible for 
insanitary products. 

The method of washing should be determined by the character of 
the soil in which the tomatoes are grown. 

Too little attention usually is given to sorting, although it is 
probably the most important step in the manufacture of clean, whole¬ 
some tomato products. Only skilled, responsible workers should be 
intrusted with this task, and, preferably, should be worked in shifts 
of not over three hours. If an apron conveyor is used, the speed 
should be carefully regulated to the capacity of the sorters. Care 
should be taken to have the feed uniform. The sorting room should 
be lighted from the top and incandescent lighting should be pro¬ 
vided for dark days. 


SANITARY CONTROL OF TOMATO-CANNING FACTORIES. 


29 


Trimming and sorting should be made separate operations. 

It is very difficult to make sanitary pulp from trimmings alone 
and its manufacture is of doubtful profit even when properly done. 

It is possible to arrange a system of manufacture by which the 
rotten trimmings can be wholly discarded and the pulp made from 
good trimmings and small tomatoes. 

The percentage of decay in the sorted stock should be 1 per cent 
or less. 

Prompt handling is essential if spoilage is to be avoided. 

Too much care can not be given to cleaning. Every piece of 
apparatus in the factory should be arranged conveniently and plenty 
of cleaning equipment should be available. The best results are 
obtained when the cleaning is highly systematized and each worker 
is made responsible for his part in it. 

Laboratory methods of checking the character of the finished 
products have been found of great value. 


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